The present invention relates to a brake actuation unit comprising a cylinder/piston arrangement which acts on at least one brake lining which can be brought into frictional engagement with a brake disk, a hydraulic pump which is hydraulically connectable with a pressure chamber of the cylinder/piston arrangement in order to move the cylinder of the cylinder/piston arrangement relative to the piston of the cylinder/piston arrangement, and a motor for driving the hydraulic pump.
From EP 286 504 B1 a hydraulic brake actuation device with an electric control system is known which comprises a body and a brake piston which is suitable for sliding in the body parallel to its axis and which together with it defines a main control chamber which is connected to a pump via a pressure line. The pump is driven via an output shaft of the electric motor. The pump is connected to a brake fluid reservoir via an inlet line. A circuit line which is controlled by a solenoid valve selectively connects the main control chamber with the reservoir. The reservoir is formed in the body. The electric motor is secured on said body. The pump has a variable volume pump chamber which is formed in said body and which is partially limited by one end of a plunger which is supported in said body and the opposite end of which is connected with the output shaft of the electric motor via a mechanism. This mechanism converts the rotational movement of the shaft into a reciprocating movement of the plunger. An inlet valve in the inlet line as well as an outlet valve are arranged in the return line in the body. The axis of the output shaft of the electric motor is aligned perpendicularly to the axis of the plunger. A crankshaft is supported by the shaft and rests resiliently against the body in order to keep the plunger permanently resting against the crankshaft.
In view of the fact that this brake actuation unit has a radial piston pump which, due to heavy pressure pulsations, does not enable adequate controllability, this arrangement is not suited for a sensitive pressure modulation, e.g. for an antislip control system. Moreover, this brake actuation unit requires an additional solenoid valve for relieving the hydraulic pressure, which results in an increased number of components. It is also disadvantageous that the pump is directly connected with the brake piston.